"[Lang] … in a jealous rage stabbed Maureen Boyce four or five times in the stomach while she sleeps and kills her," he said.

The court heard Mr Lang told police officers that Ms Boyce was "extremely distressed" the night of her death and threw her mobile phone off the balcony, because prospective buyers did not make an offer to purchase her penthouse.

It was originally on the market for $3.7 million.

Mr Meredith said Mr Lang has made no claim he acted in self-defence.

"The real issue in this case is whether it was Thomas Lang who stabbed Maureen Boyce or whether she committed suicide," he said.